Process for the recovery of fluorinated carboxylic acids
AssigneeHoechst Aktiengesellschaft
InventorsReinhold Obermeier, Gunter Stefaniak
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Abstract
Fluorinated carboxylic acids can be recovered from materials which contain them by releasing, if necessary, the carboxylic acids with sufficiently strong acids, esterifying the released acids and distilling off the esters. The esters can be advantageously directly hydrolyzed with aqueous ammonia solution to give the corresponding ammonium salts.
Claims9
A process for the recovery of fluorinated carboxylic acid emulsifiers in utilizable form from contaminated starting materials, which comprises:
- optionally releasing the fluorinated carboxylic acid from these materials in an aqueous medium with a sufficiently strong acid,
- reacting this fluorinated carboxylic acid with a suitable alcohol and
- distilling off the ester thus formed.
A process for the recovery of a fluorinated carboxylic acid emulsifier from an aqueous medium containing a salt of said fluorinated carboxylic acid emulsifier, which comprises:
- converting said salt of a fluorinated carboxylic acid to the corresponding carboxylic acid while said salt is in said aqueous medium, thereby obtaining a fluorinated carboxylic acid in said aqueous medium,
- reacting this fluorinated carboxylic acid with an alcohol which will react with said fluorinated carboxylic acid to form a volatilizable fluorinated carboxylic acid ester, thereby obtaining a volatilizable fluorinated carboxylic acid ester, and
- distilling off and recovering said volatilizable fluorinated carboxylic acid ester.
Dependencies are inferred from the claim text.